Transition-metal dichalcogenide monolayer MoSSe has been considered as an important two-dimensional semiconductor material for the study of fundamental physics in the field of charge-to-spin conversion, magneto-optical effect and spin-orbit torque for its strong Rashba spin-orbit coupling effect, tunable band gap and extremely flexibility for very large strain gradient, which make it one of the most suitable candidates for applications in spintronics, optoelectronic devices and quantum computing. Conventional methods for regulating the Rashba effect, such as external electric fields, biaxial strain, charge doping, and magnetic fields, often suffer from dielectric breakdown, continuous energy consumption, or limited tunability. In this work, the regulation of Rashba effect and electron transport properties of monolayer Janus MoSSe has been performed by constructing Ripple and Wrinkle structures for the application of strain gradient based on first-principles calculations. Pristine MoSSe exhibits an intrinsic Rashba effect due to its out-of-plane structural asymmetry together with its strong spin-orbit coupling. Our calculations show that the strain gradient induces significant charge redistribution between S and Se layers, thereby reconstructing the out-of-plane built-in electric field. As a result, the Rashba coefficient α_R of monolayer MoSSe is enhanced from 74.8 meV·Å to 208.1 meV·Å in the Ripple configuration. Bader charge analysis reveals systematic charge redistribution: Mo atoms continuously lose electrons with increasing amplitude; Se atoms rapidly gain electrons at small amplitudes (≤0.4 Å) and then saturate; S atoms exhibit non-monotonic behavior. Charge density difference maps further demonstrate that negative amplitude causes electron depletion on inner Se and accumulation on outer S, and vice versa for positive amplitude. This charge transfer modifies the asymmetric charge distribution, reconstructs the vertical built-in electric field, and thus effectively regulates the Rashba effect. Orbital-projected band structures show that with increasing amplitude, in-plane orbitals of Mo and Se (d_x²-y²,d_xy,p_x,y) gain contribution, while out-of-planepz of Se decreases, and pz of S vanishes above 1.0 Å. This orbital redistribution alters hybridization and local symmetry, regulating the out-of-plane field and Rashba splitting. The strain gradient also reduces the band gap monotonically: from 1.48 eV to ~0.40 eV at ±1.4 Å in Ripple, and to ~0.27 eV at ±1.0 Å in Wrinkle, due to stronger lattice distortion in the latter. For p-type carriers, electrical and thermal conductivities decrease monotonically, while the Seebeck coefficient is moderately enhanced. For n-type carriers, electronic thermal conductivity peaks at 0.8 Å (≈1.2 times pristine), the Seebeck coefficient increases from 2.51×10³ μV/K to 7.14×10³ μV/K at 1.0 Å, leading to a power factor enhancement of about 2.2 times. Our work demonstrates that strain gradient engineering via wrinkled structures provides a powerful and energy-efficient pathway to simultaneously control Rashba spin-orbit coupling and thermoelectric performance of two-dimensional semiconductors, opening new opportunities for low-power spintronic devices and integrated thermal management in flexible electronics.